An electrical module for use within a fuel injector for delivering fuel to an internal combustion engine is described. The electrical module has a variable length. The electrical module comprises electrical contacts for operatively connecting the electrical module to a power plug of a fuel injector. The electrical module also comprises an actuator for operatively controlling a control valve disposed within the fuel injector. The electrical module also comprises electrical conductors arranged within a protective housing. These electrical conductors provide an electrical connection between the electrical contacts and the actuator in order to provide electrical power to the actuator when the electrical contacts are operatively connected to the power plug of the fuel injector. The body of the electrical module is comprised of a compressible elastic element, such that the length of the module is variable by compressing the elastic element. Injectors including such electrical modules are also described.
1. A fuel injector for use in delivering fuel to an internal combustion engine, the fuel injector comprising:
an injector body, the injector body comprising a first conduit through which fuel flows; an electrical module arranged within the first conduit, the electrical module being of variable length and comprising electrical contacts for operatively connecting the electrical module to a power plug of the fuel injector, an actuator for operatively controlling a control valve disposed within the fuel injector, and electrical conductors arranged within a protective housing, the electrical conductors providing an electrical connection between the electrical contacts and the actuator, to provide electrical power to the actuator when the electrical contacts are operatively connected to the power plug of the fuel injector, wherein the body of the electrical module is comprised of a compressible elastic element, such that the length of the electrical module is variable by compressing the elastic element; and
a power plug for providing electrical power to the fuel injector; wherein the injector body is disposed within the fuel injector such that a back leak channel from the fuel injector passes through at least a part of the first conduit;
and wherein the injector body is provided with a second conduit, the second conduit being arranged in use to provide an input passage through the injector body for a second fuel flow, the second fuel flow being for use in mixing with a back leak fuel flow to form a back leak fuel flow mixture; and wherein the back leak fuel flow mixture is directed through at least a part of the first conduit.
2. The fuel injector of claim 1 , wherein the width of the first conduit is selected such that a clearance is formed between the walls of the first conduit and the electrical module to allow the passage of a back leaked fuel flow through the formed clearance.
3. The fuel injector of claim 1 , wherein the back leak fuel mixture comprises a back leak fuel flow generated within the fuel injector by opening of a control valve; and the input second fuel flow provided by a fuel source located external to the fuel injector.
4. The fuel injector of claim 1 , wherein the back leak fuel flow mixture is for use in cooling one or more of the following:
a) the electrical module;
b) the actuator;
c) the injector body.
5. The fuel injector of claim 1 , wherein a back leak fuel flow outlet from the back leak channel is positioned on the power plug, the power plug having a hermetic seal to prevent contact between the back leaked fuel flow and any electrical connections within the power plug.
6. The fuel injector of claim 1 , wherein a back leak fuel flow outlet from the back leak channel is positioned on the injector body, and the injector body is disposed with a third conduit joined to the first conduit, the back leak channel extending from the first conduit via the third conduit; wherein
the first conduit is disposed with a hermetic seal to prevent the passage of back leaked fuel from the first conduit to the power plug.
7. A fuel injector as claimed in claim 1 wherein the elastic element is a coil spring.
8. A fuel injector as claimed in claim 1 wherein the elastic element is a spring washer.
9. A fuel injector as claimed in claim 1 , wherein the width of the first conduit is selected such that a clearance is formed between the walls of the first conduit and the electrical module to allow the passage of a back leaked fuel flow through the formed clearance, wherein the injector body is provided with a second conduit, the second conduit being arranged in use to provide an input passage through the injector body for a second fuel flow, the second fuel flow being for use in mixing with a back leak fuel flow to form a back leak fuel flow mixture; and wherein the back leak fuel flow mixture is directed through at least a part of the first conduit.
10. A fuel injector as claimed in claim 9 , wherein the back leak fuel mixture comprises a back leak fuel flow generated within the fuel injector by opening of a control valve; and
the input second fuel flow provided by a fuel source located external to the fuel injector.
11. A fuel injector as claimed in claim 3 , wherein the back leak fuel flow mixture is for use in cooling one or more of the following:
a) the electrical module;
b) the actuator;
c) the injector body.
12. A fuel injector as claimed in claim 1 , wherein a back leak fuel flow outlet from the back leak channel is positioned on the power plug, the power plug having a hermetic seal to prevent contact between the back leaked fuel flow and any electrical connections within the power plug.
13. A fuel injector as claimed in claim 1 , wherein a back leak fuel flow outlet from the back leak channel is positioned on the injector body, and the injector body is disposed with a third conduit joined to the first conduit, the back leak channel extending from the first conduit via the third conduit; wherein
the first conduit is disposed with a hermetic seal to prevent the passage of back leaked fuel from the first conduit to the power plug.